package com.atguigu.day12;

import com.atguigu.bean.WaterSensor;
import org.apache.flink.api.common.functions.MapFunction;
import org.apache.flink.streaming.api.datastream.SingleOutputStreamOperator;
import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
import org.apache.flink.table.api.Table;
import org.apache.flink.table.api.bridge.java.StreamTableEnvironment;
import org.apache.flink.table.functions.ScalarFunction;

import static org.apache.flink.table.api.Expressions.$;
import static org.apache.flink.table.api.Expressions.call;

public class Flink06_SQL_UDF_ScalarFun {
    public static void main(String[] args) {
        //1.获取流的执行环境
        StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();

        env.setParallelism(1);

        //2.获取表的执行环境
        StreamTableEnvironment tableEnv = StreamTableEnvironment.create(env);

        //3.从端口读取数据并转为WaterSensor
        SingleOutputStreamOperator<WaterSensor> streamSource = env.socketTextStream("localhost", 9999)
                .map(new MapFunction<String, WaterSensor>() {
                    @Override
                    public WaterSensor map(String value) throws Exception {
                        String[] split = value.split(",");
                        return new WaterSensor(split[0], Long.parseLong(split[1]), Integer.parseInt(split[2]));
                    }
                });

        //4.将流转为表
        Table table = tableEnv.fromDataStream(streamSource);

        //不注册直接使用（只能在TableAPI中使用）
     /*   table.select($("id"), call(MyScalarFun.class, $("id")), $("ts"), $("vc"))
                .execute()
                .print();*/

        //先注册再使用
        tableEnv.createTemporarySystemFunction("strLen",MyScalarFun.class);

         /*     table.select($("id"), call("strLen", $("id")), $("ts"), $("vc"))
                .execute()
                .print();*/
        //SQL中使用
        tableEnv.executeSql("select id,strLen(id),ts,vc from "+table).print();

    }

    //TODO 自定义一个标量函数，一进一出 ，输入一个数据返回这个数据的字符串长度
    public static class MyScalarFun extends ScalarFunction {
        public Integer eval(String value) {
            return value.length();
        }
    }
}
